Transesophageal Doppler monitoring of acute hypervolemic hemodilution tolerance in elderly patients without cardiac disease

AIM:To assess the influence of hypervolemic hemodilution (HHD) on hemodynamics in elderly patients without cardiac disease. METHODS: We examined 20 anesthetized patients without evidence of heart disease (10 patients >65 years and 10 patients <55 years). All patients underwent HHD before surgery using 15 ml/kg of hydroxyethylstarch 200/0.5. Hemodynamics were measured by transesophageal Doppler monitoring (HemoSonicTM) during a stabilization period and at each level of hemodilution. Hematocrit (Hct), hemoglobin, blood gas and ECG were also monitored during hemodilution. RESULTS: No complications occurred in the patients during surgery and no differences in biometric data, Hct, and blood gases were observed between groups. After HHD, cardiac output (CO) increased in the control group but decreased in the elderly patients (≥65 years). The change of CO was solely the result of changes in stoke volume (SV) as the heart rate (HR) decreased in the control group but remained unchanged in the elderly patients. The stroke index (SI) increased in the control group (P<0.05 vs. before HHD) but no marked changes were seen in the elderly patients. The systemic vascular resistance (TSVR) decreased in the younger patients (P<0.05) but increased about 19% in the elderly patients after hemodilution. No statistically significant changes in any variables were found in the elderly patients after HHD. No correlation was found between changes in hemodynamics and patient ages. CONCLUSIONS: Acute HHD is not well tolerated during anesthesia by elderly patients without heart diseases. HHD leads to a decrease in cardiac output that is generated initially from a decrease in SV. The results indicate that elderly patients have a limited compensatory cardiovascular capacity during HHD.